Search results for "Asphalt"

Can crumb rubber modifier effectively replace the use of polymer- modified bitumen in asphalt mixture?

2021

Laboratory scale mechanical performances on six plant produced mixtures; three semi-dense surface courses and three dense binder courses modified with engineered crumb rubber (ECR) using the dry process are presented. The two types of mixtures produced and investigated fulfilled for the most part, the requirements of the Swiss and/or US standards regarding volumetric properties, water sensitivity and rutting. In advanced testing where no requirements exist, the dense ECR mixtures performed similar to the reference polymer modified mixtures and slightly worse for semi-dense mixtures in high temperature tests, where the binder becomes viscous in the rubber-binder composite and its ability to …

Mechanical characterisation and 3D fractional viscoelastic modelling of railway sub-ballast rubberised asphalt

Recommendation of RILEM TC237-SIB on fragmentation test for recycled asphalt

2019

This recommendation describes how to characterize the reclaimed asphalt through the fragmentation test. The guidelines given hereafter are based on the results of a round robin test organized by the RILEM Technical Committee 237-SIB ‘‘Testing and characterization of sustainable innovative bituminous materials and systems’’ and provide information on the testing procedure, data analysis and indications for the preparation of a test report.

Investigating Tools for Sustainability Assessment of Road Pavements in Europe

2022

Sustainability assessment (SA) is a method to support decision making processes through the evaluation of system effectiveness, environmental integrity, economic valuation, and social implications [1]. SA can be carried out through the application of life-cycle-based techniques for quantitative assessment, or by performing a mainly qualitative approach via sustainability rating systems (SRS). In the field of civil engineering, many SRS have been proposed, all based on assigning point values to actions that are determined to contribute to the overall sustainability of the project. However, only few of these systems can be applied specifically to compare road pavement technologies and/or main…

A life cycle scenario analysis of different pavement technologies for urban roads.

2019

In the past, lowest price was the award criterion, given that structural capacity and safety were assured. In the last years, environmental, energy, and long-term impacts have been introduced (climate change, resource depletion, energy consumption, generated solid waste, discharged water, and emissions). Unfortunately, the introduction of new pavement technologies and materials (i.e., waste plastics) affects maintenance and rehabilitation processes and call for accurate and timeliness studies and criteria. Consequently, this paper presents an energy and environmental assessment of an Italian urban road and considers different material-related scenarios that fully comply with emerging techno…

Optimisation of liquid rubber modified bitumen for road pavements and roofing applications

2020

Abstract Polymer Modified Bitumens (PMBs) are largely used for pavement and roofing membranes applications with Styrene-Butadiene-Styrene Block copolymer (SBS) playing a major role in both markets despite its constantly increasing price due to the rising demand for quality bitumen modifiers. On the other hand, there is an increasing trend of recycling end of life tyres generating Recycled Tyre Rubber (RTR) at affordable price. This investigation aims at engineering a modified bitumen with a combination of Liquid Rubber (LR), a homogeneous blend of 50–70% RTR pre-processed in combination with heavy oils, and a wax denominated Ethylene Bis Stearamide (EBS). In the first phase, the effect of L…

Improving the rheometry of rubberized bitumen: experimental and computation fluid dynamics studies

2017

Abstract Multi-phase materials are common in several fields of engineering and rheological measurements are intensively adopted for their development and quality control. Unfortunately, due to the complexity of these materials, accurate measurements can be challenging. This is the case of bitumen-rubber blends used in civil engineering as binders for several applications such as asphalt concrete for road pavements but recently also for roofing membranes. These materials can be considered as heterogeneous blends of fluid and particles with different densities. Due to this nature the two components tends to separate and this phenomenon can be enhanced with inappropriate design and mixing. Thi…

Integrating Circularity in the Sustainability Assessment of Asphalt Mixtures

2020

Rising concerns about the impacts that the road engineering industry is imposing to the environment have redirected national road authorities to firmly re-consider the sustainability implications of their operations. Lately, though, sustainability has established a forceful correlation with the Circular Economy and its principles. The road engineering industry, therefore, is moving towards more circular approaches. However, this is occurring without the assessment of the potential impacts of such a transition. For this reason, in this study, a composite indicator, namely, Environmental Sustainability and Circularity indicator (ESCi), for investigating the potential effects that increased ci…

From Laboratory Mixes to Full Scale Test: Rutting Evaluation of Bio-recycled Asphalt Mixes

2021

The present paper describes the rutting behavior of innovative mixes incorporating 50% of Reclaimed Asphalt (RA) with bio-materials. They were assessed in the laboratory and in a full-scale accelerated experiment. The innovative mixes studied here contained bio-materials especially designed to help recycling by re-activating the aged binder from RA. Four mixes were evaluated: three of them are manufactured with bio-materials, (two bio-rejuvenators and one bio-binder) and one was a control mix, which was a high modulus asphalt mix (EME2). In this study, the rutting resistance of the four mixes was first evaluated in the laboratory with both European and US methods. The full-scale test was th…

AllBack2Pave: Towards a sustainable recycling of asphalt in wearing courses

2017

Nowadays, asphalt plant technologies allow producing asphalt mixtures incorporating up to 100% reclaimed asphalt. Unfortunately policies are still behind technology and in order to suggest guidelines for a widespread use for surface courses, road managers feel the need of having a deeper understanding of optimised design strategies, information related to the handling in asphalt plants and on the performance of these mixes. This paper provides the summary of the main results and the details of the main idea behind “AllBack2Pave 2013–2015” a two-years, 500 K€ project funded by the CEDR Transnational Road Research project that evaluated the feasibility of going towards 100% recycling of aspha…